Make the curry paste. Put all the paste ingredients in a mortar and slowly pound with a pestle until they combine into a paste. Store remaining paste in a Mason jar and refrigerate for up to two weeks.
Make the curry. In a saucepan over medium heat, add coconut milk and curry paste. Bring to boil, then add fish sauce, tamarind, and palm sugar. Taste the curry, seasoning with more tamarind or palm sugar as needed. Then add cauliflower, prawns, and garlic. Turn off heat, then add torn betel leaves and Thai chiles. Squeeze a slice of lime and sprinkle salt to finish. Serve in an 8-inch coupe bowl.